The present invention relates generally to supports and, more particularly, to supports having plural joints adjustable along vertical pivots. Most particularly, the invention relates to adjustable joystick supports for power wheelchairs.
Electric powered wheelchairs are generally controlled by a joystick, which is operably coupled to electric drive motors. The joystick permits a wheelchair occupant to accelerate, steer, and stop the wheelchair. Other conventional steering means are often inappropriate and difficult for severely physically impaired wheelchair occupants to operate. Joysticks, on the other hand, allow those who are severely impaired to control the movement of a wheelchair simply by moving the joystick with a single hand to a position that corresponds to a desired direction of movement.
The joystick is preferably located where the wheelchair occupant can comfortably rest his or her arm on an armrest and operate the joystick free of discomfort. This generally requires the joystick to be placed just forward of a front portion of the armrest at a height where the joystick may be accessed by the wheelchair occupant.
The joystick is often mounted to the distal end of an elongated rod, which is disposed alongside the wheelchair armrest or a side portion of the wheelchair frame. This rod is typically releasably coupled to a bracket mounted to the armrest or the wheelchair frame. The bracket is typically formed to slideably receive the rod. Hence, the rod and the joystick carried thereby can slide forward, away from the armrest, or rearward, toward the armrest, in a direction along the longitudinal axis of the rod for length adjustment purposes.
While this joystick support has been adequate to adjust the location of the joystick device along the longitudinal axis of the rod, several operational problems are inherent in this design. For example, a locking mechanism to secure the rod relative to the bracket often must be loosened, usually by turning a knob, in order to permit the rod to slide forward or rearward. Subsequently, the locking mechanism must be tightened in order to retain the position of the joystick. Moreover, to move the joystick each time, this sequence of events must be repeated. This tends to be difficult and laborious to those severely impaired.
Another problem that has been encountered in connection with this joystick support is that the support positions the joystick forward of the armrest. Because of the wheelchair occupant""s limited mobility, it is often desirable to position the wheelchair as close as possible to a work surface, such as a table, desk, or the like, for greater access and convenience and to provide a practical working environment. Thus, in situations where the work surface is placed at a height similar to that of the joystick, the wheelchair may only be moved as close to the work surface as the joystick permits. Traditional joystick supports may be retracted somewhat in the direction along the longitudinal axis of the rod; however, without removal of the joystick, the joystick is still positioned between the armrest and the work surface.
Finally, ingress and egress to and from the wheelchair is more difficult since the joystick projects forward from the armrest because this impairs passage to and from the wheelchair.
The present invention is directed toward a support that overcomes the foregoing problems and deficiencies. A support according to the invention is comprised of a first support member formed for mounting to a wheelchair frame. A second support member is formed to carry a joystick. A pair of bars has first ends and second ends. The first ends are pivotally mounted to the first support member at spaced apart locations. The second ends are pivotally mounted to the second support member at spaced apart locations to form a four-bar pantographic linkage assembly. The four-bar pantographic linkage assembly produces pantographic movement of the second support member with the joystick carried by the second support member between an extended position and a retracted position. A latch mechanism is provided between the pair of bars for releasably securing bars together in either the extended position or the retracted position. The latch mechanism includes a magnet exposed along an inner facing side wall of at least one bar. A steel insert is exposed along an inner facing side wall of the other bar. The magnet cooperates with the steel insert to secure the bars in at least one of the extended or retracted positions.
In another embodiment of the invention, an armrest is mounted to a wheelchair frame. A joystick support is slideably mounted to the wheelchair frame adjacent the armrest. The support comprises a first support member including an elongate rod having a distal end and a first pair of mounting plates disposed on the distal end thereof proximate a front portion of the wheelchair frame. The joystick is carried by a second support member. The second support member includes a second pair of mounting plates. A pair of bars has first ends and second ends. The first ends are pivotally mounted to the first pair of mounting plates at spaced apart locations and the second ends are pivotally mounted to the second pair of mounting plates at spaced apart locations to form a four-bar pantographic linkage assembly. The four-bar pantographic linkage assembly produces pantographic movement of the second support member with the joystick carried by the second support member between an extended position and a retracted position. A latch mechanism is supported by the bars to releasably secure the bars in at least one of the retracted or extended positions. The latch mechanism includes a magnet exposed along an inner facing side wall of at least one of the bars and a steel insert exposed along an inner facing side wall of the other bar. The magnet cooperates with the steel insert to secure the bars in at least one of the extended or retracted positions.